Biscuit beetles

Description

The adult beetle is 2 - 3 mm in length, oval in shape, reddish brown in colour, with a dense covering of yellowish hairs. The young (larvae) of this insect look like a whitish maggot. When full size, they are approximately 5mm in length.

Where and how do they live?

If you find these insects in your home, it is likely that you have brought them in with an infested dry product. This could be any of the following: cereals and cereal products, pasta, spices, nuts, chocolate, dried beans, flour, rice, biscuits (including dog or cat biscuits).

Why are they a problem?

These insects will breed very quickly in the right conditions. The larvae can easily chew through packaging of other stored products and are very likely to spread to all the dried goods in your larder or food storage area. Any new products you buy of this type will also soon be affected.

How do they breed?

Over a period of about three weeks a single biscuit beetle will lay about 100 eggs. This will occur in the foodstuffs or surrounding areas. At normal temperature in 1-two weeks they hatch to produce very tiny active larvae, which wander about and enter packaging to infest the foods inside. Development from larvae to beetle takes between 2-5 months depending on conditions when the larvae will go through four moults.

They will then change to a pupal stage which will last between 9-18 days. During this time they will turn into an adult beetle. When the adult beetle comes out of its pupal case (which can take up to two weeks) it will move away from the food source and head towards a source of light (usually a window.) The adult beetle can live up to two months. During this time it does not feed.

What can I do to prevent biscuit beetles in my home?

There is no easy way to tell if any product you have purchased is infested when you bring it home. It is advisable to buy some air-tight ‘Tupperware’ type of containers, and transfer all your stored products into these as soon as possible after purchase, so that if a product is infested, the insects will not spread to other foods. Food stored in this type of container will be protected from infestation.

How can I get rid of biscuit beetles?

You will first have to identify which product(s) have introduced the infestation. Although by the time you have discovered there is a problem, it is likely other products will have been affected. It is probably safest to throw away all foods that could possibly contain these insects. Once you have done this you will need to completely clear your larder or storage cupboards. The affected areas will need treating with a crawling insect spray, available from most chemists and hardware stores. Please follow the directions on the can and use in well-ventilated area (open windows). You will need to treat all the joints where the shelves meet the side and back, and where the cupboard joins the wall.

Also if there is a worktop below the cupboard, this should also be treated side and back where it joins the wall. You should leave this for two days. (Do not put foods back in the cupboard during this time). Then you will need to wash your cupboards out with hot soapy water. Once dry you can then re-stock.